Spring return throttle actuator, method of control thereof and throttle assembly

Abstract

A spring return throttle actuator including: an electric, plural-coil DC motor having an output shaft, a throttle return spring, a gear transmission connected to the output shaft, a control unit adapted to control power supply to the DC motor, wherein the spring return throttle actuator has a movement range between closed throttle and fully opened throttle. The control unit includes a monitoring circuit adapted to monitor DC motor movement. The monitoring circuit is configured to receive signals from at least one voltage sensor adapted to sense voltage induced in at least one of the DC motor coils during a spring forced return of the throttle, and the monitoring circuit is configured to create a representation of DC motor movement based on said signals.

1 . A spring return throttle actuator having a movement range between a closed throttle and a fully opened throttle, said actuator comprising:
 an electric, plural-coil DC motor having an output shaft;   a throttle return spring;   a gear transmission connected to the output shaft;   a control unit adapted to control power supply to the DC motor; and   a monitoring circuit adapted to monitor DC motor movement, wherein said   monitoring circuit is configured to:
 receive signals from at least one voltage sensor adapted to sense voltage induced in at least one of the DC motor coils during a spring forced return of the throttle; and 
 create a representation of DC. 
   
     
     
         2 . An actuator according to  claim 1 , wherein the
 the at least one voltage sensor is configured to measure momentarily the voltage induced in at least one of the DC motor coils; and   the monitoring circuit is configured to produce a momentary representation of the amplitude of the voltage measured by said voltage sensor to diagnose the spring.   
     
     
         3 . An actuator according to  claim 1 , wherein
 the control unit comprises a bridge circuit comprising a plurality of branches, with one branch connected to each one of the coils.   
     
     
         4 . An actuator according to  claim 3 , wherein
 each branch of said branch circuit comprises a transistor switch connected to each one of the coils.   
     
     
         5 . An actuator according to  claim 1 , wherein
 the monitoring circuit is configured to compare measured rotational speed values of the DC motor to stored rotational speed profiles.   
     
     
         6 . An actuator according to  claim 1 , wherein
 the monitoring circuit is configured to compare measured angular throttle position values to stored throttle position profiles.   
     
     
         7 . A method of controlling a spring return throttle actuator having a movement range between a closed throttle and a fully opened throttle, wherein the actuator comprises an electric, plural-coil DC motor having an output shaft, a throttle return spring, a gear transmission connected to the output shaft, a control unit adapted to control power supply to the DC motor and a monitoring circuit comprising a voltage sensor, said method comprising:
 monitoring movement of the DC motor using the monitoring circuit;   sensing a voltage induced in at least one of the DC motor coils during a spring forced return of the throttle using the voltage sensor of the monitoring circuit; and   creating a representation of the DC motor movement.   
     
     
         8 . A method according to  claim 7 , wherein the DC motor comprises three coils, and wherein the
 voltage induced in at least one of the DC motor coils is sensed.   
     
     
         9 . A method according to  claim 7 , further comprising
 supplying the DC motor coils with power from each branch of a bridge circuit comprised in the control unit.   
     
     
         10 . A method according to  claim 7  further comprising
 measuring rotational speed values of the DC motor and comparing the measured rotational speed values to stored rotational speed profiles. 
 
     
     
         11 . A method according to  claim 7   further comprising measuring angular throttle position values and comparing the measured angular throttle position values to stored throttle position profiles.   
     
     
         12 . A throttle assembly comprising a throttle and a spring return throttle actuator, having a movement range between a closed throttle and a fully opened throttle, said actuator comprising:
 an electric, plural-coil DC motor having an output shaft;   a throttle return spring;   a gear transmission connected to the output shaft;   a control unit adapted to control power supply to the DC motor; and   a monitoring circuit adapted to monitor DC motor movement, wherein said monitoring circuit is configured to:
 receive signals from at least one voltage sensor adapted to sense voltage induced in at least one of the DC motor coils during a spring forced return of the throttle; and 
 create a representation of DC motor movement based on said signals. 
   
     
     
         13 . A throttle assembly according to  claim 12 , wherein:
 the voltage sensor is configured to measure momentarily the voltage induced in at least one of the DC motor coils; and   the monitoring circuit is configured to produce a momentary representation of the amplitude of the voltage measured by said voltage sensor to diagnose the spring.   
     
     
         14 . A throttle assembly according to  claim 12 , wherein the control unit comprises a bridge circuit comprising a plurality of branches, with one branch connected to each one of the coils. 
     
     
         15 . A throttle assembly according to  claim 14 , wherein each branch of said branch circuit comprises a transistor switch connected to each one of the coils. 
     
     
         16 . A throttle assembly according to  claim 12 , wherein the monitoring circuit is configured to compare measured rotational speed values of the DC motor to stored rotational speed profiles. 
     
     
         17 . A throttle assembly according to  claim 12 , wherein the monitoring circuit is configured to compare measured angular throttle position values to stored throttle position profiles.